The most common microphone-array-based speech enhancement method utilizes a beam forming characteristic of an array. According to different implementation manners, existing beam forming technologies may be divided into Delay and Sum Beam Forming (DSBF) and adaptive beam forming technologies. The DSBF method proposed by Flanagan in 1985 is the simplest DSBF method. At first, time compensation is performed on a speech signal received on each microphone in an array to implement speech synchronization of each channel, and then the signal of each channel is added and averaged. Under such a condition, once the signals are deviated from a direction of the array, the array may provide different gains for signals of different frequencies, thereby causing processing distortion of the bandwidth signals.
The other type of beam forming technology corresponding to the DSBF technology is adaptive beam forming technology. The adaptive characteristic of the adaptive beam forming technology is reflected in variation of a filter coefficient along with variation of a statistical characteristic of an input signal. A Generalized Sidelobe Canceller (GSC) proposed by Griffth and Jim in 1982 is a universal model of an adaptive beam former. However, in a GSC algorithm, output of a Block Matrix (BM) usually includes an effective speech component, so that an original speech may be damaged in a filter result.